The INS Vikrant, one of the world's biggest naval vessels at a length of 262 metres (860 feet), will formally enter service after 17 years of construction and tests.

It inherits the name of a retired carrier famed for enforcing a blockade against Pakistan's naval forces during the 1971 Bangladeshi independence war.

"Today, INS Vikrant has filled the country with a new confidence, and has created a new confidence in the country," Prime Minister Narendra Modi said at the ship's commissioning ceremony in southern Kerala state.

"We've joined the league of those select nations who can construct such large aircraft carriers at home," he added.

Around 1,600 sailors will crew the Vikrant, which will initially service fighter jets redesignated from India's only other aircraft carrier.

That vessel was bought second-hand from Russia, which has long been a major arms supplier to New Delhi.

Modi's government has sought to wean the country off its dependency on foreign military purchases and build a domestic defence hardware industry.

It has invested heavily in local construction, with more than three dozen other naval ships and submarines currently being built in the country's shipyards.

The outlay comes at a time of increasing concern among military top brass over the strategic challenge posed by China's increasing presence in the Indian Ocean.

Last month New Delhi joined Washington in raising security concerns when neighbour Sri Lanka allowed a port visit by a Chinese research vessel accused of spying activities.

India and the United States are both members of the so-called Quad, a security alliance focused on the Indo-Pacific and aimed at providing a more substantive counterweight to China's rising military and economic power.

"The security concerns of the Indo-Pacific and the Indian Ocean region were ignored in the past but it is our top priority today," Modi said.

- 'Sign of our subjugation' -

Friday's commissioning ceremony also saw the unveiling of a new naval flag without a British colonial symbol left over from India's colonial era.

The new ensign replaces a prominent Saint George's Cross, the national flag of England, with the royal seal of the Hindu warrior-king Chhatrapati Shivaji.

"It is a historic date, we've made history and discarded a sign of our subjugation," Modi said during his address.

Shivaji is lauded by many for challenging the Muslim Mughal dynasty, which ruled much of the subcontinent prior to British colonisation, and which Hindu nationalists see as an era of foreign subjugation.

The ruling Bharatiya Janata Party has also backed a $300 million, 210-metre-tall statue of Shivaji off the coast of Mumbai, to be unveiled later this year.